This user gets it!
For anyone reading this who hasnt been to church in a while, if ever - if this sounds nice to you, please stop in! We'de love to have you, and we hope you'll enjoy our company. I lived as an Atheist for about a decade and they welcomed me in.
Believe it or not, I'm right there with you. I had a simuilar story, my mom got me a puppy when I was about 11 or 12 and at the time, my family had just fallen apart (divorce), and I was alone and angry. Poor doggo, like yours, loved me unconditionally even tho I was usually cold towards him, pushed him away, was mean, etc.
I was lucky, in that he's still around (still lives back home, although hes an old doggo now, still as sweet as can be). It might sound lame, but one day visiting my folks, it was just him and me alone, I got down on the floor and gave him a big hug, told him that I was deeply sorry and regretted everything, and would never treat him like that again. He just leaned on me and wagged his tail.
I maintain that based doggos know everything we say, and everything that happens around them. I think he forgave me, probably years ago.
Anyway, as you've clearly repented, I believe that Jesus has forgiven you 100%, and likely, your doggo did also, again, years ago.
You clearly wont do it again, so dont be too hard on yourself.
Most people either have time or money. If you have money, I'd consider giving to a REPUTABLE charity or shelter near you, that cares for animals on the street. If you dont have money, but have time, thats just as well, they can always use volunteers, or you can talk to folks and try to find homes for their animals.
I'm kind of rambling here, but I hope this helps you. I'll pray for your internal peace, my brother...